user
Explain the concept of 'code smell'.

assistant
Code smell is a term used to describe characteristics of code that can indicate poor design choices or poor programming practices. Common code smells include duplication, lack of modularity, lack of clarity, and excessive complexity. Code smell can lead to problematic designs which can make code more difficult to maintain and test in the future. It is important for developers to be aware of code smells, as they can be a sign that the code could be refactored or improved.